Interesting, never heard the second use anywhere, Must be a Polish thing.

It actually stands for a lot of things outside of fucking.

"przyjebać" - to punch someone
"najebać" - to fuck someone up
also "najebać (się)" - to get wasted
"wjebać" - to eat
"wyjebać (się)" - to trip and fall
"zjebać" - to screw up
"ojebać" - to run sb down (as in criticize, deride)